Motor driven hand tool



0a. 31, was. A A LARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4. 1926 5 sheets-sheet 1 A.A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 5 Shegts-Sheet 2'HHQQ'IWW" Oct. 31, 1933 A. A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL 7 Original Filed Qct. 4, 1926 5 Sheets-Sheet 5 num i iwllhl Oct. 31, 1933. A. A. CLARKE 1,932,511

' MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 5 Sheets-Sheet 4#ZZZZ JQ I J1 Oct. 31, 1933.

A. A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 s Sheet-Sheet 5 1 HmII m m m IIIH um, 11 I Patented Oct. 31, 1933 UNITED STATES PATENTOFFICE MOTOR DRIVEN HAND TOOL Alex A. Clarke, Chicago, Ill., assignor toThomas B. Bennett, Muskegon, Mich.,

jointly and himself Application October 4, 1926, Serial No. 139,271Renewed August 17, 1932 23 Claims.

to permit convenient and accurate guidance thereof by the hand of anoperator during the cutting operation-and to constitute a stable,substantially self-supporting structure; the combination of the toolwith a base arranged to bear on the work to be cut and so related to thetool as to fully define the character of the cutting operations inrespect to the depth of the cut, and the angle thereof; an adjustablejoint between the base and the cutting tool for co-relating thedirection of the movement of the cutting disk with respect to themovement of the base; the utilization of the base as a guard protectingthe operator against accidental contact with the cutting blade when thetool is out of operation; gauge means associated with the tool forpredetermining the depth of the cut and the angular relation thereof tothe piece to be cut, and for performing special cutting operations;indicating means associated with said tool for conveniently determiningthe cutting adjustments; the utilization of the ventilating arrangementof the electric driving motor of the tool for removing the wasteparticles produced by the cutting tool from near the cutting edgethereof; and other features that will appear more fully from thefollowing specification and claims, taken in connection with theaccompanying drawings in which,

Fig. 1 is a longitudinal vertical sectional view of a motor-driven handsaw made according to my invention;

Fig. 2 is a fragmentary elevational view of the tool handle, showing thelocking arrangement and indicator for determining the angularity of thecut; 1

Fig. 3 is a top plan of the tool, a portion of the power transmissionhousing being broken away to show the interior arrangement thereof;

Fig. 4 is a sectional view through the device shown in Fig. 1 along theline IVIV;

Fig. 5 is a transverse sectional view through the fan housing and handleof the motor along the lines V-V in Fig. 1;

Fig. 6 is an elevational view of the cutting tool, from the back of Fig.1;

Fig. '7 is a plan view of the base guide of the toolshown in Figs. 1 to6 for predetermining the direction of the cutting operation and theadjustment for miter cutting;

Fig. 8 is a view partially in section, and partially in elevation, ofthe gauge and indicator for 0 determining the depth of the cut, combinedwith 'means for resiliently projecting the base away from the cuttingdisk to serve as a guard therefor;

Fig. 9 is an end-elevational view of the tool 5 from the front thereofwhile engaged in making an angular cut;

Fig. 10 is a plan view of the tool as shown in Fig. 9, while making acut that is straight with respect-to the edge of a board but under anangle against the surface thereof;

Fig. 11 is a view similar to Fig. 10, showing the tool engaged in makinga miter cut, also under an angle against the surface of the work-piece;

Fig. 12 is a view similar to Fig. 1 of an arrangement embodying amodification of my invention;

Fig. 13 is an end elevational view of the tool shown in Fig. 12, fromthe back thereof, with the base provided with a ripping-gaugeattachment;

Fig. 14 is a fragmentary-plan view of a portion of thebase and theassociated ripping gauge attachment shown in Fig. 13.

In Figs. 1 to 11 is shown an embodiment of my invention which includes apower-driven tool unit comprising a motor unit 1, having substantiallyrigidly attachedthereto a tool holder, or carrier, andtransmission-housing unit 2, in which is mounted a cutting disk or saw3. These several units are so associated with a hand grip or handle 4and a base 5 for supporting and guiding the tool on a work-piece, suchas a board 6, as to secure a cutting tool of universal utility, capableof performing all operations in which it was heretofore necessary to usea number of hand driven cutting tools, or large power driven machines.The arrangement of the several parts constituting my improved cuttingtool is such that it is capable of performing by means of electricalpower drive the operations of hand driven saws, with a high degree ofaccuracy, and in predetermined adjustable relation to the piece to beworked. The various operations are carried on by my improved tool withvery great speed, and the several parts thereof are so arranged as tosecure a stable support and guidance during the operation of the tooland throughout the handling thereof, with substantially entireelimination of the danger of injury to the operator or other objects inthe neighborhood of the tool.-

Thehigh degree of stability of my improved tool and the ease of handlingthe same is to a large extent secured by the particular grouping of themotor unit 1 and the tool housing 2, with the tool 3, in front thereof,and the handle 4, so related thereto that the masses are so distributedas to be substantially in equilibrium, and self-supporting when broughtin contact with a work-piece. The tool so constructed requires little,or no, efiort on the part of the operator while handling the same. Inview of the very dangerous character of power-driven circular saws, theelimination of the hazard to the operator, by the above describedarrangement of the several parts constituting the tool unit, not onlyfacilitates the actual work that is to be performed but by removing themetal hazard usually associated with danger, it enables him to performmore work with greater accuracy and skill.

The details of the structure of my improved tool appear clearly in theaccompanying drawings. The motor unit 1 comprises a small powerfulelectric motor 11, of familiar design, having a rotor 12 provided with adriving shaft 13 journaled in suitable bearings 14 held in the endmembers 15 of a tubular motor housing 16. In the position shown in Fig.1 of the drawings, illustrating the tool engaged in cutting a board 6,the motor axis and shaft 13, with the associated housing 16, areinclined, the forward ends thereof pointing downwardly in the directionin which the cutting operation proceeds.

Extending directly away from the front end of the motor housing 16 ismounted the tool housing on carrier frame 2, and the circular cuttingtool or disk saw 3, the frame being so shaped that the circular cuttingdisk 3 is preferably in substantial alignment with a medial planethrough the axis of the motor 11. In the position shown in Fig. 1 thecutting disk is disposed in a vertical medial plane through the motor11.

The tool carrier 2 has a tubular frusto conical flange member 21 forrigidly securing the same to the front end of the motor housing. Thenarrow end of the flange member 21 constitutes a neck 22 fromone side ofthe center of which extends a substantially semi-circular wall 23disposed on one side of the circular cutting disk for supporting thesame and guarding one side thereof. The periphery of the semi-circulartool guard and supporting wall 23 has a laterally extendingcircumferential guard rim 24 overlapping and protecting the upperportion of the circumference of the cutting disk 3.

The cutting disk 3 is detachably mounted, at its center, on a shaft 26which is journaled in bearings 2'] held in the walls of a transmissioncasing or housing 28 laterally extending from the guard wall 23 on theside opposite the saw disk 3. The transmission casing 28 constitutes anelongated chamber extending substantially parallel to the axis of themotor and encloses the power transmitting mechanism comprising a gearwheel 31 fixed to the front end of the motor shaft 13, to drive a pinion32 secured to one end of a counter-shaft 33, the other end of which isprovided with a worm 34 for driving a worm wheel 35 mounted on the diskshaft 26 for rotating the disk 3. In order to suitably support thecounter-shaft 33 and the associated gearing mechanism 32, 34, 35, ballbearings 36 and the bearings 2'? are suitably held in wall portions ofthe transmission housing 28, the latter diyiding into a number ofdistinct chambers surrounding the individual parts of the transmissionmechanism.

For the successful operation of a hand guided motor driven tool of thetype here considered it is of utmost importance that vibrations incidentto the operation of power transmission mechanisms should be eliminated.The tool carrier and the associated transmission housing shown a in thedrawings have been designed with particular view to elimination of anypossible sources of vibrations that might be caused by misalignment ofthe individual parts. To this, end the transmission housing 28 and thetool guard and carrier 23, 24, are preferably made in the form In theform of the casting shown in the draw ings, the seating surfaces forholding the bearings 36 which support the counter-shaft 33, may bemachined from the two open ends of the housing, one end being on theside of the flange 21 by which the tool carrier is held against themotor housing, the other opening being-at the opposite end of thelongitudinal chamber, which opening, in the assembled completed tool, 3is enclosed by a suitable cover 37.

The seat surface for the inner ball bearing 27 which holds one end ofthe disk shaft 26, is

similarly machined from an opening in the part of the transmissionchamber surrounding saidshaft on the side opposite the saw, said openingbeing enclosed by a suitable cover 39 which has a seat member for theouter disk, shaft bearing 27.

The entire structure may be stiffened by suitable ribs 40 extendingbetween the several parts of the tool carrier frame. The handle 4 forholding the tool unit, mentioned before, is preferably made as anintegral part of the motor housing 16, and, as pointed out above,extends laterally away from the motor housing in the direction of theplane of the cutting disk, toward the workpiece. In the arrangementshown in the drawing, the axis of the handle 4, and the imaginary lineconnecting the center of the cutting disk with the front of the motor,constitute diverging straight lines extending from the front end of themotor shaft towards the surface of the board 6, or other piece which isto be cut. A triggerlike button 42 in the handle is arranged to suitablycontrol the energization of the motor .11 through the switch 43, forinstance, to have the motor running only as long as the button isdepressed.

The motor housing 16 with the integral handle 4, as well as the combinedtool-carrier and transmission housingZ, are each made of singlecastings, preferably of aluminum to reduce as much as possible theweight of the tool and avoid a 7' multiplicity of parts that are to beassembled and aligned.

The above-described tool unit comprising the motor with the forwardlyprojecting cutting disk and the downwardly extending grip 4 constitute astructure which is in itself well adapted to perform most of the cuttingoperations usually carried out by hand saws, the entire tool beingrelatively light, with the parts so balanced that by holding the grip 4the cutting disk 3 will be easily guided in the direction in which thecut is to be made. This guidance is facilitated by the coplanararrangement of the cutting disk and the grip.

The divergent support of the grip and the cut-- weights of the toolparts, supporting the tool principally on the work-piece, and the handof the operator serving principally for directing the cutting blade.

The foregoing arrangement places the center of gravity of the tool unitat a point in the motor back of the place where the grip is joinedthereto. Accordingly, when approaching the work the preponderant weightof the tool unit acts somewhat back of the handle, so that little eifortis required by the operator holding the grip to support the tool. Thevertical line from the center of gravity will then intersect the line ofthe arm back of the handle.

On the other hand, when the cutting disk is tilted forwardly during thecutting operation, the center of gravity of the tool unit will come tolie so that the vertical line therefrom will intersect the line betweenthe lower end of the grip and the cutting edge, thus relieving theoperator from substantially all efforts in carrying the tool. Inparticular, by resting the lower side 43 of the transmission housingagainst the surface of the object to be cut, and also resting the lowerend of the grip 4 on said surface, very extended cutting operations maybe accurately carried out without strain on the operator.

In order to secure full balance of the forces involved in operating thetool, the motor drive of the cutting disk is so arranged that, whenviewed in the direction toward Fig. 1, the disk 3 rotates incounter-clock-wise direction, causing the cutting teeth to underbite theobject that is being cut, thus pulling the tool towards the object, thereactional forces from the cutting disk exercising a stabilizationpressure on the handle 4.

While the foregoing tool as described above will perform all of theoperations, usually carried out with hand saws, in a very eflicient way,its usefulness and field of application is greatly increased through theprovision of the aforementioned base 5 which serves to, increase theaccuracy with which the cutting disk may be'guided on the work-piece,eliminates substantially all strain on the operator while carrying outcutting operations, and permits close determination of the depth of thecut as well as the angle thereof with respect to the outer surface ofthe work-piece. The base is also arranged to act as a guard protectingthe operator against accidental contact with the cutting blade when thetool is removed from the work-piece.

In the preferred construction shown in the drawings, the base 5has theshape of an elongated, relatively fiat tray, the bottom member of whichconstitutes a face plate 51 arranged to bear against the surface of thework 6, that is to be cut. The face plate 51 has a centrally disposed,longitudinal slot 52 through which the cutting edge of the saw may beprojected toward the work-piece 6. The tool unit is suitably mounted onthe base so as to permit the cutting disk 3 to be projected through theslot 52. In the preferred embodiment of my invention, this mountingcomprises a double-pivotal, or gimbal, joint between the lower end ofthe grip 4 of the tool unit and the back end portion 53 of the base 5.The joint between the grip 4 and the base 5 comprises a cross-piece54extending between the upstanding side wall portions 55 of the base 5,the cross-piece being pivoted at its ends to said side pieces by meansof pins 56 to permit swinging movement of the cross-piece around saidpins. Approximately in the center of the cross-piece 54, there isprovided an upwardly projecting ear 5'7 which extends between twosimilarly shaped downwardly extending ear members 58 at the lower end ofthe grip 4 to provide by means of a suitable pin 59, preferably in theform of a screw threaded stud, a second pivotal connection around whichthe grip, with the motor unit and tool unit rigidly connected thereto,may be tilted sldewise in a direction transverse to .the direction ofthe cutting disk or blade 3.

The double pivotal connection of the handle to the base 5 thus permits adouble swinging or tilting movement of the tool unit and the associatedcutting disk with respect to the base 5. The first-mentioned pivotalconnection, through the pivots 56, permits swinging or tilting movementof the tool and the blade in the direction of the cutting operation,thus making it possible to project more or less of the cutting bladethrough the slot 52 in the face plate 51, for regulating the depth ofthe cut. The second pivotal connection, through the pivot 59, permitsswinging or tilting movement of the tool and cutting disk 3 in adirection transverse to the direction of the cutting operation forvarying the angle under which the cutting disk 3 penetrates into thesurface of, the object to be out While the first adjustment thus permitsvariations of the depth of the cut, the second adjustment permits theproduction of bevel or chamfered cuts and edges.

The foregoing arrangements for varying the depth as well as theangularity of the out are combined with provisions for pre-setting anddetermining the depth or the angularity before the cutting operation isbegun, and with indicating means for readily showing the depth andangularity.

To this end I may provide, somewhat in front of the grip 4, on one sidethereof, a depth gauge 61 comprising an upwardly projecting rod 62 whichis joined at its lower end to an upwardly projecting ear 63 on the base5. The connection between the base ear 63 and the lower end of the gaugerod 62 is in the nature of a universal joint permitting forward andsidewise tilting movement of the rod 62 corresponding to the tiltingmovements of the tool unit described above, as by means of a doublepivotal connection composing pivots 64 and 65, shown clearly in Fig. 8of the drawings. The upper end of the gauge rod is provided with athreaded perforation into which may be screwed an extension rod 66, theupper end of which has a head 67 adapted to act as a stop against whichthe lower side of the transmission housing 28 contacts to prevent adownward swinging movement of the tool unit beyond a point determined bythe contact of said gauge head 67 with said transmission housing 28. The

thread on the extension rod 66 may be cut away on one side thereof andprovided with a graduation for indicating the depth of the cut. Theextension rod 66, when adjusted, may be fixed with respect to theswinging rod 62, as by means of a lock nut 68.

The tilting angle under which the cutting operation is carried on mayalso be readily predetermined by means of the pivot pin 59 at the bottomof the handle 4, the pin having its outer end screw threaded andprovided with a lock nut and washer for locking the joint and fixing theangular position of the tool with respect to the base. A pointer '71fixedly related to the base 5 cooperates with a suitable graduation 72on the back of the handle, making it possible to read off the angleunder which the cutting disk is tilted.

As far as I am aware the foregoing construction provides the firstarrangement of a portable, motor-driven circular hand saw whereby bevelor chamfered cuts may be carried out with the same accuracy as washeretofore possible only with heavy, substantially immovable cuttingmachines. The high degree of accuracy of the cutting operation isgreatly due to the arrangement of the base 5, the sides of which embracethe cutting disk throughout the full width of its cutting engagementwith the work-piece. The forward, substantially-closed end of the faceplate 51, which may be rested upon the work-piece in advance of thebeginning of the cutting operation, also greatly aids the operator inmaking the correct approach to the work, and, to correctly start thecutting operation.

A distinct feature of my invention is the arrangement for projecting thebase 5 away from the cutting tool, so that, when the tool is moved awayfrom the work, the face plate 51 constitutes a guard that protects theoperator, or other objects in the neighborhood, against accidentalcontact with the cutting disk 3. This arrangement may be secured, forinstance, by the provision of a ring slidably surrounding the hinge rod62 of the depth gauge 61, the ring being pivotally connected to theadjacent portion of the guard wall 23 of the tool housing as at 76. Acompression spring 77 is provided around the lower portion of the hingerod 62 and arranged to upwardly press against the ring 75, therebytending to swing the base away from the cutting disk. This movement islimited by the abutment of the flanged upper end of the hinge rod 62against the upper side of the ring 75.

In order to conveniently guide the tool, particularly for starting thecutting operation, it may be provided with an additional handle 78 thatmay be fixed by a threaded bolt screwed into a suitable threaded hole,either in the neck portion of the tool, at 79, or into the motor housing16, at 80, or vertically on the guard rim of the tool housing, at 81, orat the side of the guard rim 24, at 82.

When making straight cuts on a fiat surface, as shown in Figs. 1 to 6,the tool is held with one hand on the grip and lifted above thework-piece, with'the front edge of the base resting on the edge of thepiece to be cut. The spring 77, which holds the base projected away fromthe tool, is preferably so arranged that the weight of the tool whentilted forwardly around the pivots 56 will bring the cutting edge incontact with the surface of the work-piece, when the motor is put intorotation, the underbiting action of the cutting teeth will pull thecutting disk into the body of the work until the lower side of thetransmission housing 28 will come in contact with the head 67 of thedepth gauge and. thus stop further downward movement of the cuttingedge. However, if necessary, a force exercised by the hand which guidesthe grip 4 will lift the cutting edge out of the groove, the weight ofthe motor being so balanced around the grip that the force necessary forlifting the saw will be relatively small.

When making angular cuts with a tool having the particular constructionof the pivotal connection between the grip 4 and the base 5, shown inFigs. 1 to 11, it is necessary to make the proper adjustments withrespect to the depth, as well as to the angularity of the cut in advanceof the cutting operation. To this end the tool is first swung until aportion of the cutting disk 3, corresponding to the desired depth of theout is projecting through the longitudinal slot 52 in the face plate51,the disk being held at said depth by clamping the ring 75 surroundingthe gauge rod 62, as by means of a wing screw 85. With the ring 75 sofixed on the gauge rod 62, there will be no further swinging movement ofthe base with respect to the tool around the pivots 56 in the directionof the cutting plane, but the tool is still free to be adjusted aroundthe pivot 59 at the lower end of the grip 4 for fixing the angle underwhich the cutting disk is inclined towards the surface of the face plate51. After the tool is tilted to the desired degree, as shown by pointer71 on the scale 72 at the back of the grip 4, the tool is locked in thisposition and is ready to be applied for performing the desired cuttingoperation, as

shown in Fig. 9. The additional handle 78, may, if desired, be used inany of the foregoing operations either during the preliminary steps inmaking the approach to the work-piece or during the entire operation.

The utility of my improved tool is still further increased by combiningtherewith a gauge or guide for pre-fixing the angle under which thecutting disk moves forwardly in the work-piece. To this end the lefthand side of the base 5, when viewed from the back of the tool, isprovided with two upstanding ear posts 91, carrying a guide rod 92,which may be secured in suitable perforations in the ears by means ofset screws 93. A slide member 94 is mounted on the guide rod 92 and hasa suitable bracket 95, a straight-edge or rule member 96 projectingdownwardly below the face plate 51 of the base. The straight-edge 96 ismounted in the bracket member 95 of the slide 94 by means of a bolt andnut attachment 97 permitting the straight edge to be locked in anydesired angular direction with respect to the sliding movement of theslide 94 lengthwise of the base 5. The direction of adjustment of thestraightedge 96 on the bracket 95 may be read off by means of a suitableindicator 98 and a co-operative graduation 99 on the bracket member.

When the tool is out of operation, the slide 94, with the straight edge96 downwardly projecting therefrom, is pulled toward the front end ofthe base 5 through the action of a cable 101 operated by a suitablespring wheel 102, the cable passing over a pulley 103, to hold the slide94 towards the front end of the guide rod 92.

If a straight out is desired the straght-edge 96 is adjusted in adirection perpendicular to the direction of the cut, and the forward endof the base 5, and the straight edge 96 downwardly projecting therefrom,are brought in contact with the front side of the work-piece, such asthe board 6, until the straight edge 96 is in line therewith. The toolmay then be pressed forwardly and the cutting operation carried out, thebase sl ding forwardly, being guided by the slide 94 to secure thedesired direction of the out. g

If a miter cut is desired, with the drection of the saw inclined towardsthe side of the board that is to be cut, the straight edge is lockedunder the desired angle with respect to the guide rod 92, and the baseand the straight edge 96 at the forward end thereof are brought incontact with the front edge of the board to be worked on, as in the casedescribed above. On forward movement of the tool, the cutting disk willnow proceed in a direction inclined against the directhe adjustment ofthe straight edge 96, the entire tool with the base sliding forwardly inthe slide 94 under the predetermined angle.

By adjusting the straight edge 96 for a miter cut, and locking thehandle to give the cutting disk 3 an angle with respect to the faceplate51, a double bevel cut may thus be easily carried out.

Figs. 10 and 11 show my improved tool while making a bevel cut in adirection straight to the side of a board, and under an angle thereto,respectively.

To further facilitate the handling of my improved tool, I also providemeans for removing the waste particles produced by the action of thecutting tool on the board or other work-piece. To this end, a fan 101,is arranged to provide an air blast that may be utilized to remove saidwaste particles from near the cutting edge of the disk 3.

In the embodiment of my invention shown in Figs. 1 to 11, the'fan 101 isadapted to suck air through the motor towards the front end thereof,expelling the blast of air so created through perforations 102 disposedalong the circumferenceof the housing and thereby cooling the motor. Atone point of the perforated circumference, there is provided an exit 103to which may be attached a flexible hose 104, the forward end of whichterminates in a nozzle 105 held at the edge of the slot 52 in the base5, so that an air blast through the nozzle will blow away the wasteparticles tending to accumulate in front of the cutting edge. By makingthe air pressure generated by the fan in the front end of the housingsufficiently large, a powerful air blast will be produced at the nozzle,and by mounting the nozzle in definite relation with respect to the faceplate 51 the blast will always be directed in prefixed relation to thepoint where the cutting edge.

emerges from the surface of the body that is being cut.

In the modification of my invention shown in F." gs. 12 and 13, thedouble pivotal connection between the tool unit and the base 5 is soarranged as to permit swinging movement of the cutting disk 3, whenmaking cuts in a direction perpendicular to the surface of thework-piece, as well as when making bevel cuts, with the plane of thecutting disk disposed at an angle to the surface of the work-piece. Thisresult is secured by changing the order in which the two pivotal axes inthe joint between the grip 4 in the base follow each other. Thus, inFigs. 12 and 13, the axis of the first pivotal connection 111 nearest tothe base is arranged to provide tilting movement of the handle 4 and thetool in the direct on transverse to the cutting movement of the saw,thus permitting adjustment of the angle under which the cutting disk isinclined to the face plate 51, for varying the angle of the cut. Theaxis of the second pivotal connect on 112 is so arranged, thatjwith thefirst pivotal connection 111 locked, the tool may be freely swung in thedirection of the cutting plane towards, and away from, the surface ofthe work-piece for varying the depth of the cut as well as forpermitting withdrawal of the tool from the slot 52 in the face plateduring the cutting operation, as in the caseof straight cuttingoperations with that form of the tool shown in Figs. 1 to 11.

- Furthermore, in order to secure correct indications of the depth ofthe cut with a single gauge, the depth gauge 61, which is similar tothat of the modification shown in Figs. 1 to 11, is placed in the planeof the cutting disk, with the hinge connection of the gauge rod 62 soarranged as to cause the depth gauge to swing with the tool within theentire range of adjustments thereof,

The modified tool shown in Figs. 12 and 13 also provides for removal ofthe cutting waste from in front of the cutting edge through suctioninstead of through blow action, thus leaving the surroundings of thecutting tool free from v waste particles, and eliminating dust laden airfrom the neighborhood of the operator. To this end, the motor housingmay have, between the suction fan 101 and the rotor 12 of the electricmotor, a suct'on or vacuum chamber 115, the rotating fan 101 sucking airfrom the vacuum chamber 115 and expelling the same into a relativelyporous bag 116 held on one side of the motor housing 16, the airescaping from the bag through the pores thereof. A hose 117, having oneend terminating near the front edge of the cutting dsk, is so connectedto the vacuum chamber 115 that the rotation of the fan 101 sucks throughthe hose 117 the produced waste particles, and expels the same into thebag 116 from where they may be removed.

It is'very often desirable to use a saw of the above described characterfor cutting longitudinal strips in a board, or the like, and to this endI may provide the base of the tool, such as shown in Figs. 1 to 11,'orFigs. 12 and 13, with a ripping gauge 121, a plan view of which is shownin Fig. 14. In the constructon shown in the drawings, the slide 94 hasbeen removed from the guide rod 92 by releasing the set screws 93 andsliding the guide rod out from the ear posts 91. Instead of the slide94, two guide members 122 may then be slid, or, if necessary, fixed, onthe guide rod 92, and the rod with the guide members again secured inplace in the ears 91. The guide members 122 have laterally projecting,slotted guides 123 to which may be secured clamp 115 bolts 124 whichhold, at their lower end, a ripping gauge in the form of a straight rodthat is parallel to the direction in which the cutting disk is toproceed. The guide members 122 are provided with graduation scales toper- 120 mit close determination of the width of the piece to be cut,and the clamping bolts 124 may then be suitably locked in position. Theripping gauge 121 will then project downwardly below the level of thepiece to be cut, and bear thereagainst for 125 guiding the cutting diskthrough'the operation.

The two forms described above are intended as illustrations of the waysin which the many novel features characterizing my invention may bepractically applied. As shown, my new tool has the weight and the massesof the various parts so distributed that the tool is balanced in thehand of the operator and relieves him from excessive stresses. Thearrangement of the base for guiding the tool and for permitting closedetermination of the depth of the cut,-as well as of the angle thereof,is another outstanding feature of my invention. Associated with theforegoing functions of the tool is also an arrange- 'ment whereby thebase may be projected away cutting surface. The tool is thus adapted foroperation not only at right angle lines, as in the conventionalcross-cutting of lumber, but also for miter and bevel cuts. Theutilization of the ventilating means of the motor for removing thesawdust or waste from in frontof the cutting tool is another featurewhich greatly increases the utility of the tool. In the accompanyingclaims I desire to cover not only the individual elements forcharacterizing the various novel features present in my improved tool,but also the various combinations thereof which greatly contribute toits utility as well as to the universality of its applications.

I claim as my invention:

1. In a motor-driven hand tool, a motor, a circular cutting disksupported by said motor and rotated thereby for performing cuttingoperations, a base having a face adapted to engage the surface of thepiece to be out, said base having a slot permitting said tool to beprojected therethrough against said surface to. cut the same, a gripjoining said motor and the associated tool to said base for guiding saidtool and said base over the surface to be cut, and an adjustableconnection on said grip for adjustably fixing the angle under which thecutting disk projects through said slot with respect to the face of saidbase.

2. In a motor-driven cutting tool, the combination with a power unitcomprising a motor, a circular cutting disk supported at the front endof said motor and driven therefrom, and a handle laterally extendingfrom said motor for supporting the same and said cutting disk by anoperator, of a base unit having a pivotal connection with said handlefor guiding and supporting said power unit during cutting operations,said base unit having a slot permitting said disk to be projectedtherethrough towards a work-piece when swung around-said pivotalconnection, the masses of said power unit being so distributed withrespect to said handle that when said base unit is swung away from saidpower unit a perpendicular line from the center of gravity of said powerunit to the base will intersect the same at a point back of said handle,and when said cutting disk is swung toward said base to carry outcutting operations a perpendicular line from said center of gravity willintersect said base at a point in front of said handle.

3. In a motor-driven cutting tool, the combination with a power unitcomprising a motor, a circular cutting disk supported at the front endof said motor and rotated thereby, and a handle laterally extending fromthe front end of said motor for gripping said tool by an operator, of abase unit having a face adapted to bear against a work-piece forsupporting and guiding said powerunit during cutting operations, apivotal connection between said handle and said base unit for joiningthe same to permit swinging movement of said base toward and away fromsaid cutting disk, said base having a slot permitting said cutting diskto be swung therethrough toward said work-piece for cutting operations,means tending to yieldably swing said base away from the cutting disk,the masses of said power unit being so distributed with respect to saidhandle that the preponderant weight of said power unit acts back of saidhandle when power unit acts in front of said handle when the disk of thepower unit is swung into said slot.

4. In a motor-driven cutting tool, the combination with a power unitcomprising a motor, a circular cutting disk supported at the front endof said motor and rotated thereby, and a handle laterally extending fromthe front end of said motor for gripping said tool by an operator, of abase unit having a face adapted to bear against a work-piece forsupporting and guiding said power unit during cutting operations, apivotal connection joining said handle to said base unit to permitswinging movement of said base toward and away from said cutting disk,said base unit having a slot to project said cutting disk therethroughtoward a work-piece for cutting operations, means tending to yieldablyswing said base away from the cutting disk, the masses of said powerunit being so distributed with respect to said handle that aperpendicular line from the center of gravity of said power unit to theface of said base unit intersects said face substantially back of saidhandle when said base is swung away from the disk, and intersects saidface in front of said handle when said cutting disk is swung toward saidslot to perform cutting operations.

5. In a cutting tool, a motor housing, a rotary motor mounted in saidhousing, a cut-ting disk extending in front of one end of said motorhousing and supported therefrom, a handle extending on one side of saidhousing in the plane of said cutting disk for guiding and supporting thesame, said disk being rotated by said motor, a base having a faceadapted to bear against the surface of a work-piece, said base having aslot for exposing a portion of the cutting diskcorresponding to thedepth of the out toward the work-piece,

a pivotal connection joining said handle to said base for varying theangle between the plane of the cutting disk and the face of the base tovary the direction under which the cutting disk penetrates into thepiece to be out.

6. In a cutting tool, a tubular motor housing, a rotary motor mounted insaid housing, a cutting disk extending in front of one end of said motorhousing and supported therefrom, a handle extending on one side of saidhousing for guiding and supporting the same, said disk being rotated bysaid motor, and a base having a face adapted to bear against the surfaceof a work-piece, said base having an opening for exposing a portion ofthe cutting disk corresponding to the depth of the out toward thework-piece, a pivotal connection joining said handle to said base forvarying the angle between the plane of the cutting disk and the face ofthe base, means for locking said pivotal connection to secure apredetermined cutting angle with respect to the face, and additionalpivotal connecting means interposed in the connection between saidhandle and said base to permit swinging movement of said cutting disktoward and away from the work-piece during the cutting operation withoutaffecting the angle of the cut.

7. In a motor-driven hand tool, a rotary motor having a casing enclosingthe same, a tool housing rigidly supported at one end of said motorhousing in the direction of the axis of rotation thereof, a circularcutting disk rotatably mounted in said tool housing, in a directionsubstantially parallel to the motor axis, power transmitting meansinterconnecting said motor and said cutting disk to rotate the latterfor performing cutting operations, said tool housing having acompartment completely enclosing said power transmitting means, a handlerigidly extending from said motor housing for guiding the motor and thecutting disk during the cutting operations, said handle and said cuttingdisk being disposed in a median plane of said motor, a base having aface plate for supporting said cutting disk on the surface of the bodyto be cut, said face plate having a slot for exposing said cutting disktowards said surface, a pivotal connection between said handle and saidbase plate permitting said disk to be swung through said slot toward andaway from said base plate to vary the exposed depth thereof, resilientmeans tending to swing said base away from said disk for interposingsaid face plate as a guard in front of the cutting edge of said diskwhen removed from the work-piece,'and adjustable gauge means for fix--ing the depth of the cut comprising an adjustable stop limiting theextent to which the disk may be swung towards said face plate, and aportion thereof exposed through said slot.

8. In a motor-driven hand tool, a base having a face plate adapted tobear on the surface of an object to be cut, a cutting tool comprising amotor and a circular cutting disk supported by said motor and rotatedthereby, said base having an opening through which said disk may beprojected to perform the cutting operation, means for so supporting saidtool from said base as to secure a predetermined relationship betweenthe plane of the cut and the plane of the face plate,

. a guide adapted to fixedly bear against the object to be cut, saidbase being held in sliding engagement with said guide to permit relativemovement therebetween, and means for fixing the relative direction ofsaid movement to determine the direction of the cutting operation onsaid object, said guide being longitudinally movable along said base inthe direction of the cutting operation, and means for automaticallybringing said guide to the point on said base where it is located whenstarting a cutting operation.

9. In a motor-driven hand tool, a base having a face plate adapted tobear on the surface of an object to be cut, a cutting tool comprising amotor and a circular cutting disk supported by said motor and rotatedthereby, said base plate having a longitudinal slot extending parallelto the direction in which the tool is to cut, means for so supportingsaid motor and the associated cutting disk from said base as to cause aportion of the said disk to project through said slot to exposetherethrough a portion of the disk corresponding to the depth of thecut, 'a cutting guide comprising a guide member adapted to be fixedlyheld against the object to be cut for determining the direction of thecutting operation, a gliding connection between said member and saidbase to permit said guide member to move longitudinally along said baseparallel to the direction. of said slot along said base, resilient meanstending to normally hold said guide at the front end of said base, saidguide being so arranged that said base glides forwardly on said guidemember while proceeding in the cutting operation.

10. In a motor-driven hand tool, a base having a face plate adapted tobear on the surface ofan object to be cut, a cutting tool comprising amotor and a circular cutting disk supported by said motor and rotatedthereby, said base plate having a longitudinal slot extending parallelto the direction in which the tool is to cut, means for so supportingsaid motor and the associated cutting disk from said base as to causesaid disk to project through said slot exposing'therethrough a portionof the disk corresponding to the depth of the cut, a cutting guideslidably mounted on said base to permit longitudinal movement thereofparallel to the direction of the slot, said guide comprising asubstantially straight-edge member projecting below the plane of saidface plate and adapted to bear against a side of an object to be cut,and means for so adjustably fixing the direction of said straight-edgemember with respect to the sliding movement thereof in said base as tosecure predetermined angular movement of the cutting plane with respectto said side of the object to be cut.

11. In a motor-driven hand saw, an electric driving motor, a tubularhousing enclosing said motor, a handle downwardly extending from saidhousing near the front end of said motor, a unitary tool housingsupported in front of the end of said motor housing near said handle,acircular saw disk rotatably supported in said tool housing to rotate ina medial plane through said motor and said handle, power transmittingmeans interconnecting said motor and said disk to rotate the latter,said unitary housing comprising a substantially semi-circular guardextending over the upper part of the cutting edge of said'disk on theside substantially opposite to the line interconnecting the end of thehandle and the center of the disk, bearing means in a side wall of saidguard for journaling said cutting disk, said power transmitting meansbeing disposed on the other side of said guard wall, and a transmissionhousing enclosing said power transmitting means, the

lower surfaces of said unitary tool housing and said handle constitutinga substantially co-planar supporting base and guide for said tool unit.

, 12. In a motor-driven hand tool, a power unit including a motor and acutting disk supported and driven by said motor, a base adapted to bearagainst and slide on the work during the cutting operation, a supportingconnection between sai base and said power unit, a guide slidablyarranged on said base adapted to be held fixed with respect to said workduring the cutting operation, and means for normally returning saidguide to a predetermined position on said base.

13. In a hand-portable motor-driven saw, a power unit comprising a motorand a saw disk supported at one end of said motor and driven thereby,the plane of said disk extending longitudinally in front of said motor,a base plate underlying said power unit and arranged so that thelongitudinal extension thereof is intersected by the line of gravity ofsaid power unit, and a pivotal connection between said power unit andsaid base plate for pivoting said power unit about an axis lying in theplane of said disk to bring said disk under adjustable inclination tothe surface to be out, said pivotal connection being arranged to permitswinging movement of said disk into the work in inclined position.

14. In a motor-driven cutting tool, a power unit ISO comprising a motor,a circular cutting disk exg tending along a medial plane through saidmotor and supported by said motor and driven therefrom, a baseunderlying said power unit and directly bearing against the surface tobe cut for guiding said motor and the associated cutting disk, and aconnection between said power unit and said base for pivoting said powerunit about an axis lying in the plane of said disk to bring saiddisk'under adjustable inclination to the surface to be cut, andpermitting variation of the depth of the out while carrying out thecutting operation.

it. In a hand-portable motor-driven saw, a power unit comprising amotor, a circular saw disk substantially vertically supported on thefront end of said motor and driven thereby, said saw disk extendinglongitudinally in front of said motor, a guard enclosing the upper edgeof said saw and exposing for cutting action only the downward edge ofthe saw, and a depending han= dle downwardly extending from theunder-side of said motor at its forward end and backward thereunder sothat the weight of said motor is above said handle.

16. In a hand-portable motor-driven saw, a power unit comprising amotor, a circular saw disk substantially vertically supported on thefront end of said motor and driven thereby, said disk extendinglongitudinally in front of said motor, a guard enclosing the upper edgeof said saw and exposing for cutting action only the downward edge ofthe saw, and a depending handle downwardly extending from the under-sideof said motor near the end on which said saw disk is supported.

1'7. In a portable saw, a tubular motor housing, a rotary motor axiallymounted in said housing, a saw disk longitudinally extending insubstantially vertical direction in front of one end of said motorhousing and supported from said housing, a handle extending from thefront end of said housing downwardly away therefrom for guiding andsupporting said saw, and a guard enclosing the upper edge of said sawand exposing for action only the downward edge of the saw, the masses ofthe several members of said saw being so distributed that thepreponderant weight thereof acts back of the handle, when the same isgripped by an operator to hold the saw in approaching the work. I

18. In a motor-driven cutting tool, a motor, a handle downwardlyextending from the front end of said motor and having its lower'endadapted to engage the work, and a saw disk supported on the end of saidmotor in front of said handle in a substantially vertical plane, saidsaw disk being rotated by said motor in a direction in which thereactive forces exercised on said tool during the cutting operation tendto press said handle against the work that is being cut to act as asupport for said tool.

19. In a hand-portable motor-driven saw, a power unit comprising amotor, a circular saw disk substantially vertically supported on thefront end of said motor and driven thereby, said saw disk extendinglongitudinally in front of said motor, a guard enclosing the upper edgeof said saw and exposing for cutting action only the downward edge ofthe saw, and a depending handle downwardly extending from the under-sideof said motor so that the weight of said motor is above said handle,said handle lying in substantially the same plane as said saw disk.

. through said slot.

wagon 20. In: a hand-portable motor-driven saw, a power unit comprisinga motor, a circular saw disk substantially vertically supported on thefront end of said motor and driven thereby, said disk extendinglongitudinally in front of said motor and having a relatively largediameter so that its lower edge projects downwardly for a substantialdistance beyond the lower edge of said motor, a guard enclosing theupper edge of said saw and exposing for cutting action only the downwardedge of the saw, and a depending handle downwardly extending from theunderside of said motor near the end on which said saw disk issupported.

21. In a hand-portable motor-driven saw, a power unit comprising a motorand a circular saw disk supported longitudinally in front of one end ofsaid motor and driven thereby, a base plate for guiding and supportingsaid saw having a supporting face suficient to support said saw instable equilibrium throughout the normal range of operation thereof, thelower edge of said disk being directed against said base, and adepending handle having its upper end connected to the under-- side ofsaid motor near the end on which said 1 cutting disk is supported, andits lower end movably connectedto said base plate.

22. In a hand-portable motor-driven tool, a power unit comprising amotor and a circular saw disk supported longitudinally at the front end1 of said motor and driven thereby, a depending handle having its upperend connected to the under-side of said motor near the front endthereof, a base plate movably joined to the lower end of said handle andarranged to always intersect the transverse plane of the center ofgravity of said power unit and stably support the same, said base platehaving a slot for projecting therethrough the cutting edge of said diskfor performing cutting rperations, and means for q yieldably holdingsaid base plate in front of said cutting edge to act as a guardtherefor.

23. In a hand-portable motor-driven tool, a power unit comprising amotor and a circular saw disk supported longitudinally at the front endof said motor and driven thereby, a depending handle having its upperend connected to the under-side of said motor near the front endthereof, a base plate movably joined to the lower end of said handle andarranged to always intersect the, transverse plane of the center ofgravity of said power unit and stably support the same, said base platehaving a slot for projecting therethrough the cutting edge of said diskfor performing cutting operations, means for yieldably holding said baseplate in front of said cutting edge to act as a guard therefor, and anadjustable stop for determinedly limiting the extent to which the diskmay be swung towards said base plate, and aportion thereof projectedtowards the work 1 ALEX A. CKE.

